Dual Polarized Antenna Isolation via Inductive Compensation Line
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Solution Overview
Problem
Dual polarized antennas face challenges in achieving effective isolation due to capacitive coupling between feeders, which existing solutions fail to adequately address, particularly when the coupling occurs via the radiating part of the antenna or results in unwanted signal interference.
Innovation Solution
A compensation line with a short electrical length and high impedance is connected between the feeders, acting as an inductive element to cancel out capacitive coupling, thereby enhancing antenna isolation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a compensation path is arranged between transmitting and receiving signal paths to cancel unwanted signals, then isolation between antenna ports is improved, but the solution only works for specific signal paths and does not address capacitive coupling between feeders
Solution Approach 1:
An intermediary feeder is introduced between the first and second feeders, connected at a first point to the first feeder and at a second point to the second feeder. This intermediary feeder acts as a mediator to provide an additional signal path that enables cancellation of unwanted signals resulting from capacitive coupling between the feeders, thereby extending the compensation capability to cover both direct antenna-to-antenna coupling and feeder-to-feeder capacitive coupling.
2Reliability
If signal paths are adapted to have specific length differences to cancel unwanted signals, then cancellation of specific coupling is achieved, but other unwanted signals from different couplings are not cancelled
Solution Approach 1:
The signal cancellation function is segmented into multiple independent paths: the original transmitting and receiving signal paths for canceling antenna-to-antenna coupling, and a new compensation path through the intermediary feeder for canceling feeder-to-feeder capacitive coupling. Each path can be independently optimized with appropriate length differences to cancel specific types of unwanted signals, allowing comprehensive cancellation of multiple coupling mechanisms simultaneously.
3Reliability
If antenna element size is increased to achieve efficient signal cancellation, then isolation performance is improved, but the physical size and cost of the antenna element increases
Solution Approach 1:
The intermediary feeder serves as a compact mediator that provides an additional signal path without requiring significant increases in antenna element size. By routing the compensation signal through this intermediary feeder with appropriate length adjustments, efficient cancellation of unwanted signals is achieved while maintaining a compact overall antenna structure, avoiding the need to scale up the entire antenna element.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution efficiently compensates for capacitive coupling between feeders and the radiating part, achieving improved antenna isolation with a compact, cost-effective design that maintains radiation patterns and reduces cross-polarization interference.
Implementation Method 1
capacitive coupling between the feeders themselves
Implementation Method 2
the compensation line has a short electrical length and a high impedance relative to an impedance of the first and second feeders, thereby giving the compensation line an essentially inductive character
Data Source
AI summary
A dual polarized antenna element having improved antenna isolation is disclosed by the present invention. The antenna element includes a first feeder for feeding the antenna element in a first polarization direction, and a second feeder for feeding the antenna element in a second polarization direction. According to the present invention, a compensation line is arranged between the first and the second feeders for compensating for an imbalance caused by an essentially capacitive coupling between the first and second feeders. The compensation line is connected to the first and second feeders in close proximity to a radiating part of said antenna element, and has a short electrical length θ and a high impedance relative to an impedance of the first and second feeders, respectively, thereby giving the compensation line an essentially inductive character.